'\" te
.\"  Copyright 1989 AT&T
.\" Copyright (C) 2004, Sun Microsystems, Inc. All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
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.TH REXEC 3SOCKET "Feb 10, 2004"
.SH NAME
rexec, rexec_af \- return stream to a remote command
.SH SYNOPSIS
.LP
.nf
\fBcc\fR [ \fIflag\fR ... ] \fIfile\fR... \fB-lsocket\fR \fB -lnsl \fR [ \fIlibrary\fR... ]
#include <netdb.h>
#include <unistd.h>

\fBint\fR \fBrexec\fR(\fBchar **\fR\fIahost\fR, \fBunsigned short\fR \fIinport\fR, \fBconst char *\fR\fIuser\fR,
     \fBconst char *\fR\fIpasswd\fR, \fBconst char *\fR\fIcmd\fR, \fBint *\fR\fIfd2p\fR);
.fi

.LP
.nf
\fBint\fR \fBrexec_af\fR(\fBchar **\fR\fIahost\fR, \fBunsigned short\fR \fIinport\fR, \fBconst char *\fR\fIuser\fR,
     \fBconst char *\fR\fIpasswd\fR, \fBconst char *\fR\fIcmd\fR, \fBint *\fR\fIfd2p\fR, \fBint\fR \fIaf\fR);
.fi

.SH DESCRIPTION
.LP
The \fBrexec()\fR and \fBrexec_af()\fR functions look up the host \fIahost\fR
using \fBgetaddrinfo\fR(3SOCKET) and return \fB\(mi1\fR if the host does not
exist. Otherwise \fIahost\fR is set to the standard name of the host. The
username and password are used in remote host authentication. When a username
and password are not specified, the \fB\&.netrc\fR file in the user's home
directory is searched for the appropriate information. If the search fails, the
user is prompted for the information.
.sp
.LP
The \fBrexec()\fR function always returns a socket of the \fBAF_INET\fR address
family. The \fBrexec_af()\fR function supports \fBAF_INET\fR, \fBAF_INET6\fR,
or \fBAF_UNSPEC\fR for the address family. An application can choose which type
of socket is returned by passing \fBAF_INET\fR or \fBAF_INET6\fR as the address
family. The use of \fBAF_UNSPEC\fR means that the caller will accept any
address family. Choosing \fBAF_UNSPEC\fR provides a socket that best suits the
connectivity to the remote host.
.sp
.LP
The port \fIinport\fR specifies which \fBDARPA\fR Internet port to use for the
connection. The port number used must be in network byte order, as supplied by
a call to \fBhtons\fR(3C). The protocol for connection is described in
detail in \fBin.rexecd\fR(8).
.sp
.LP
If the call succeeds, a socket of type \fBSOCK_STREAM\fR is returned to the
caller, and given to the remote command as its standard input and standard
output. If \fIfd2p\fR is non-zero, an auxiliary channel to a control process is
set up and a file descriptor for it is placed in *\fIfd2p\fR. The control
process returns diagnostic output (file descriptor 2), from the command on the
auxiliary channel. The control process also accepts bytes on this channel as
signal numbers to be forwarded to the process group of the command. If
\fIfd2p\fR is 0, the standard error (file descriptor 2) of the remote command
is made the same as its standard output. No provision is made for sending
arbitrary signals to the remote process, other than possibly sending
out-of-band data.
.sp
.LP
There is no way to specify options to the \fBsocket()\fR call made by the
\fBrexec()\fR or \fBrexec_af()\fRfunctions.
.SH RETURN VALUES
.LP
If \fBrexec()\fR succeeds, a file descriptor number is returned of the socket
type \fBSOCK_STREAM\fR and the address family \fBAF_INET\fR. The parameter
*\fIahost\fR is set to the standard name of the host. If the value of
\fIfd2p\fR is other than \fBNULL\fR, a file descriptor number is placed in
*\fIfd2p\fR which represents the standard error stream of the command.
.sp
.LP
If \fBrexec_af()\fR succeeds, the routine returns a file descriptor number of
the socket type \fBSOCK_STREAM\fR in the address family \fBAF_INET\fR or
\fBAF_INET6\fR, as determined by the value of the \fIaf\fR parameter.
.sp
.LP
If either \fBrexec()\fR or \fBrexec_af()\fR fails, \fB\(mi1\fR is returned.
.SH ATTRIBUTES
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
MT-Level	Unsafe
.TE

.sp
.LP
This interface is Unsafe in multithreaded applications. Unsafe interfaces
should be called only from the main thread.
.SH SEE ALSO
.LP
.BR htonl (3C),
.BR gethostbyname (3NSL),
.BR getaddrinfo (3SOCKET),
.BR getservbyname (3SOCKET),
.BR socket (3SOCKET),
.BR attributes (7),
.BR in.rexecd (8)
